This invention relates generally to lubricating oil compositions and methods of reducing exhaust emissions, reducing fuel consumption and cleaning combustion chambers of internal combustion engines.
The International Lubricant Standardization and Approval Committee (ILSAC) GF-2 specification requires passenger car motor oils to provide enhanced fuel economy in a modern low friction engine (ASTM Sequence VI-A). Previous investigations have indicated that the choice of detergent system and friction modifier used in a motor oil has a large impact on the fuel economy of the lubricant. Further studies indicate that detergent systems can affect tailpipe emissions.
Emissions from internal combustion engines are the primary cause of air pollution in many cities and metropolitan areas. Such emissions include uncombusted hydrocarbons, hydrocarbons formed in the combustion process, sulfur oxides, nitrogen oxides, and particulate matter. To attempt to reduce the quantities of these emissions, the federal and state governments have imposed emission standards. These standards typically apply to new engines but have also been applied on a fleet-average basis to include previously manufactured engines in the emission reduction strategy. Over time, the standards have required lower and lower levels of emissions. New standards have been proposed that will further significantly reduce the level of emissions that will be permitted. There have, accordingly, been many and diverse attempts to reduce the levels of emissions, both of newly manufactured engines and of previously manufactured engines, through modification and add-on equipment programs.
A fundamentally sound way to reduce the level of vehicle emissions is by reducing the amount of fuel consumed during operation.
Hydrocarbon emissions are undesirable because of the role they play in air pollution and also because they represent an energy loss from that available in the hydrocarbon fuel. Sulfur oxides not only contribute to local air pollution, but also are the principal cause of acid rain. Urban smog is caused primarily by nitrogen oxides (NOx). The black smoke of engine exhaust is typically caused by particulate emissions which add to the local air pollution and may cause health problems, including cancer, known to be caused by the polycyclic aromatic compounds in the solvent organic fraction of the particulates.
The levels of emissions of an engine are interrelated by complex and poorly understood mechanisms. It is known, for example, that adding anhydrous alcohol to gasoline reduces the hydrocarbon content of the fuel, and also tends to reduce the levels of emitted particulates and carbon monoxide. Increasing the temperature of the in-cylinder combustion usually results in more complete combustion of the fuel, reducing hydrocarbon emissions, but also results in increased nitrogen oxides and affects the polycyclic aromatic hydrocarbon constituents of the particulates. Sulfur oxide emissions can be reduced by using low sulfur fuels, but it is known that reducing sulfur in the fuel normally changes the aromatics and boiling range of the fuel, both of which affect the amount of particulates emitted.
As noted above, at the same time, improved fuel economy is required.
U.S. Pat. No. 4,326,972 (Chamberlin, Ill, Apr. 27, 1982) relates to fuel economy of internal combustion engines, especially gasoline engines, which is improved by lubricating such engines with specific lubricant compositions in which the essential ingredients are a specific sulfurized composition and a basic alkali metal sulfonate. Additional ingredients may include at least one oil-dispersible detergent or dispersant, a viscosity improving agent, and a specific salt of a phosphorus acid.
U.S. Pat. No. 4,952,328 (Davis et al., Aug. 28, 1990) describes a lubricating oil formulation which is useful in internal combustion engines. More particularly, lubricating oil compositions for internal combustion engines are described which comprise (A) at least about 60% by weight of oil of lubricating viscosity, (B) at least about 2.0% by weight of at least one carboxylic derivative composition produced by reacting (B-1) at least one substituted succinic acylating agent with (B-2) from about 0.70 equivalent up to less than one equivalent, per equivalent of acylating agent, of at least one amine compound characterized by the presence within its structure of at lest one HN less than group, and wherein said substituted succinic acylating agent consists of substituent groups and succinic groups wherein the substituent groups are derived from a polyalkene, said polyalkene being characterized by an {overscore (M)}n value of about 1300 to about 5000 and an {overscore (M)}w/{overscore (M)}n value of about 1.5 to about 4.5, said acylating agents being characterized by the presence within their structure of an average of at least 1.3 succinic groups for each equivalent weight of substituent groups, and (C) from about 0.01 to about 2% by weight of at least one basic alkali metal salt of sulfonic or carboxylic acid. The oil compositions of the invention also may contain (D) at least one metal dihydrocarbyl dithiophosphate and/or (E) at least one carboxylic ester derivative composition, and/or (F) at least one partial fatty acid ester of a polyhydric alcohol, and/or (G) at least one neutral or basic alkaline earth metal salt of at least one acidic organic compound. In one embodiment, the oil compositions of the present invention contain the above additives and other additives described in this specification in amounts sufficient to enable the oil to meet all the performance requirements of API Service Classification SG.
U.S. Pat. No. 5,256,322 (Cohu, Oct. 26, 1993) relates to a lubricating oil for use in methanol fueled internal combustion engines, the lubricating oil having a total base number from 9.0 to about 14.0 and comprising:
a) a suitable base oil;
b) overbased sodium-sulfonate in an amount sufficient to provide a base number from about 1.0 to about 2.0 in said lubricating oil; and
c) at least one metal sulfonate selected from the group consisting of overbased calcium sulfonate, overbased magnesium sulfonate and mixtures thereof in an amount sufficient to provide a base number from about 8.0 to about 12.0 in said lubricating oil.
U.S. Pat. No. 5,562,864 (Salomon et al., Oct. 8, 1996) describes a lubricating oil composition which comprises a major amount of an oil of lubricating viscosity and
(A) at least about 1% by weight of at least one carboxylic derivative composition produced by reacting
(A-1) at least one substituted succinic acylating agent containing at least about 50 carbon atoms in the substituent with
(A-2) from about 0.5 equivalent up to about 2 moles, per equivalent of acylating agent (A-1), of at least one amine compound characterized by the presence within its structure of at least one HN less than group; and
(B) an amount of at least one alkali metal overbased salt of a carboxylic acid or a mixture of a carboxylic acid and an organic sulfonic acid sufficient to provide at least about 0.002 equivalent of alkali metal per 100 grams of the lubricating oil composition provided that when the alkali metal salt comprises a mixture of overbased alkali metal salts of a hydrocarbyl-substituted carboxylic acid and a hydrocarbyl-substituted sulfonic acid, then the carboxylic acid comprises more than 50% of the acid equivalents of the mixture; and either
(C-1) at least one magnesium overbased salt of an acidic organic compound provided that the lubricating composition is free of calcium overbased salts of acidic organic compounds; or
(C-2) at least one calcium overbased salt of an acidic organic compound provided that the lubricating composition is free of magnesium overbased salts of acidic organic compounds.
U.S. Pat. No. 5,726,133 (Blahey et al., Mar. 10, 1998) is directed to a low ash natural gas engine oil which contains an additive package including a particular combination of detergents and also containing other standard additives such as dispersants, antioxidants, antiwear agents, metal deactivators, antifoamants and pour point depressants and viscosity index improvers. The low ash natural gas engine oil exhibits reduced deposit formation and enhanced resistance to oil oxidation and nitration.
U.S. Pat. No. 5,804,537 (Boffa et al., Sep. 8, 1998) relates to a low phosphorus passenger car motor oil containing an oil of lubricating viscosity as the major component and a tri-metal detergent mixture as a minor component, wherein the tri-metal detergent mixture comprises at least one calcium overbased metal detergent, at least one magnesium overbased metal detergent and at least one sodium overbased metal detergent, wherein the tri-metal detergent mixture is present in the oil composition in an amount such that the total TBN contributed to the oil composition by the tri-metal detergent mixture is from about 2 to about 12, and wherein the calcium overbased detergent contributes from about 8 to about 42% of the total TBN contributed by the tri-metal detergent mixture, the magnesium overbased detergent contributes from about 29 to about 60% of the total TBN contributed by the tri-metal detergent mixture, and the sodium overbased detergent contributes from about 15 to about 64% of the total TBN contributed by the tri-metal detergent mixture.
This invention is directed to a lubricating oil composition comprising a major amount of an oil of lubricating viscosity and an additive system comprising
(A) from about 0.1 to about 5% by weight of a detergent composition, comprising at least two metal overbased compositions wherein said detergent composition consists essentially of
(A-1) at least one alkali metal overbased detergent and
(A-2) at least one calcium overbased detergent, wherein the ratio of total base number on a per 100 TBN and diluent-free basis contributed by the alkali metal detergent to the total base number contributed by the calcium detergent ranges from about (99.5-20) to about (0.5-80);
(B) from about 1 to about 10% by weight of a succinimide dispersant; and
(C) from about 0.1 to about 5% by weight of a metal dihydrocarbyl dithiophosphate of the formula 
wherein R1 and R2 are each, independently, hydrocarbyl groups containing from 3 to 13 carbon atoms, M is a metal and n is an integer equal to the valence of M.
Also included are methods for reducing fuel consumption and exhaust emissions of internal combustion engines and methods for cleaning the combustion chamber thereof.
In the method of this invention, the combustion chamber of an internal combustion engine is cleaned utilizing a NOx emission-reducing amount of a lubricating oil composition comprising components (A), (B), and (C). Within this invention, the words xe2x80x9ccleanedxe2x80x9d, xe2x80x9ccleanxe2x80x9d or xe2x80x9ccleaningxe2x80x9d signify removal of particulate solids from the combustion chamber in the case of a combustion chamber that contains deposits and/or the prevention or reduction of particulate solids build-up in the combustion chamber. The lubricating compositions of this invention also provide a fuel-economy improving benefit.
As used herein, the terms hydrocarbyl substituent, hydrocarbyl group, hydrocarbon group, and the like, are used to refer to a group having one or more carbon atoms directly attached to the remainder of a molecule and having a hydrocarbon or predominantly hydrocarbon character. Examples include:
(1) purely hydrocarbon groups, that is, aliphatic (e.g., alkyl, alkenyl or alkylene), alicyclic (e.g., cycloalkyl, cycloalkenyl) groups, aromatic groups, and aromatic-, aliphatic-, and alicyclic-substituted aromatic groups, as well as cyclic groups wherein the ring is completed through another portion of the molecule;
(2) substituted hydrocarbon groups, that is, hydrocarbon groups containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the group (e.g., halo, hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
(3) hetero substituted hydrocarbon groups, that is, hydrocarbon groups containing substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen. In general, no more than two, and in one embodiment no more than one, non-hydrocarbon substituent is present for every ten carbon atoms in the hydrocarbon group.
In general, no more than about three nonhydrocarbon groups or heteroatoms and preferably no more than one, will be present for each ten carbon atoms in a hydrocarbyl group. Typically, there will be no such groups or heteroatoms in a hydrocarbyl group and it will, therefore, be purely hydrocarbyl.
The hydrocarbyl groups are preferably free from acetylenic unsaturation. Ethylenic unsaturation, when present will generally be such that there is no more than one ethylenic linkage present for every ten carbon-to-carbon bonds. The hydrocarbyl groups are often completely saturated and therefore contain no ethylenic unsaturation.
The term xe2x80x9clowerxe2x80x9d as used herein in conjunction with terms such as hydrocarbyl, alkyl, alkenyl, alkoxy, and the like, is intended to describe such groups which contain a total of up to 7 carbon atoms.
As used herein, the expression xe2x80x9cconsisting essentially ofxe2x80x9d permits the inclusion of substances which do not materially affect the basic and novel characteristics of the composition under consideration. Accordingly, the expressions xe2x80x9cconsists essentially ofxe2x80x9d or xe2x80x9cconsisting essentially ofxe2x80x9d mean that the recited embodiment, feature, component, etc. must be present and that other embodiments, features, components, etc., may be present provided the presence thereof does not materially affect the performance, character or effect of the recited embodiment, feature, component, etc. The presence of impurities or a small amount of a material that has no material effect on a composition is permitted. Also, the intentional inclusion of small amounts of one or more non-recited components that otherwise have no material effect on the character or performance of a composition is still included within the definition of xe2x80x9cconsisting essentially ofxe2x80x9d.
The expression xe2x80x9ctotal base numberxe2x80x9d (TBN) refers to a measure of the amount of acid (perchloric or hydrochloric) needed to neutralize the basicity of a product or a composition, expressed as milligrams KOH/gram of sample. It is measured using Test Method ASTM D-2896.
Oil of Lubricating Viscosity
The lubricating compositions of this invention employ an oil of lubricating viscosity, including natural or synthetic lubricating oils and mixtures thereof. Mixtures of mineral oil and synthetic oils, particularly polyalphaolefin oils and polyester oils, are often used.
Natural oils include animal oils and vegetable oils (e.g. castor oil, lard oil and other vegetable acid esters) as well as mineral lubricating oils such as liquid petroleum oils and solvent-treated or acid treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Hydrotreated or hydrocracked oils are included within the scope of useful oils of lubricating viscosity.
Oils of lubricating viscosity derived from coal or shale are also useful. Synthetic lubricating oils include hydrocarbon oils and halosubstituted hydrocarbon oils such as polymerized and interpolymerized olefins, etc. and mixtures thereof, alkylbenzenes, polyphenyl, (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.), alkylated diphenyl ethers and alkylated diphenyl sulfides and their derivatives, analogs and homologues thereof and the like.
Alkylene oxide polymers and interpolymers and derivatives thereof, and those where terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute other classes of known synthetic lubricating oils that can be used.
Another suitable class of synthetic lubricating oils that can be used comprises the esters of dicarboxylic acids and those made from C5 to C12 monocarboxylic acids and polyols or polyether polyols.
Other synthetic lubricating oils include liquid esters of phosphorus-containing acids, polymeric tetrahydrofurans, alkylated diphenyloxides and the like.
Unrefined, refined and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can used in the compositions of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils often are additionally processed by techniques directed to removal of spent additives and oil breakdown products.
Specific examples of the above-described oils of lubricating viscosity are given in Chamberlin III, U.S. Pat. No. 4,326,972 and European Patent Publication 107,282, both of which are hereby incorporated herein by reference for relevant disclosures contained therein.
A basic, brief description of lubricant base oils appears in an article by D. V. Brock, xe2x80x9cLubrication Engineeringxe2x80x9d, Volume 43, pages 184-5, March, 1987, which article is expressly incorporated by reference for relevant disclosures contained therein.
(A) The Detergent
At least two metal overbased detergent compositions are present as (A-1) and (A-2). Component (A-1) is at least one alkali metal overbased detergent and (A-2) is at least one calcium overbased detergent. Overbased detergents used in this invention are prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is usually an acid, usually an acid selected from the group consisting of aliphatic substituted sulfonic acids, aliphatic substituted carboxylic acids and aliphatic substituted phenols. The alkali metals comprise at least one of lithium and sodium with sodium being preferred.
While an alkali metal overbased detergent and a calcium metal overbased detergent are both present, they are usually present as separately overbased compositions. That is, an alkali metal overbased composition and a calcium overbased composition are separately prepared then incorporated into the lubricating oil composition. Two separate metal overbased compositions are used. However, an acid simultaneously overbased with both sodium and calcium containing reagents is also useful in the instant invention.
The terminology xe2x80x9coverbasedxe2x80x9d, relates to metal salts (sulfonates, carboxylates and phenates) wherein the amount of metal present exceeds the stoichiometric amount. Such salts are said to have conversion levels in excess of 100% (i.e., they comprise more than 100% of the theoretical amount of metal needed to convert the acid to its xe2x80x9cnormalxe2x80x9d, xe2x80x9cneutralxe2x80x9d salt). The expression xe2x80x9cmetal ratioxe2x80x9d, often abbreviated as MR, is used in the prior art and herein to designate the ratio of total chemical equivalents of metal in the overbased salt to chemical equivalents of the metal in a neutral salt according to known chemical reactivity and stoichiometry. Thus, in a normal or neutral salt, the metal ratio is one and in an overbased salt MR is greater than one. They are commonly referred to as overbased, hyperbased or superbased salts and are usually salts of organic sulfur acids, carboxylic acids, or phenols.
The alkali metal overbased detergent typically has a metal ratio of at least 10:1, preferably at least 13:1 and most preferably at least 16:1. The calcium overbased detergent typically has a metal ratio of at least 10:1, preferably at least 12:1 and more preferably at least 20:1.
Sulfonic acids include the mono- or poly-nuclear aromatic or cycloaliphatic compounds which, when overbased, are called sulfonates. The oil-soluble sulfonates can be represented for the most part by the following formulae:
[R3)xxe2x80x94Txe2x80x94(SO3)y]zMfxe2x80x83xe2x80x83(I)
[R4(SO3)g]hMixe2x80x83xe2x80x83(II)
In the above formulae, M is a metal cation as described hereinabove; T is a cyclic nucleus such as, for example, benzene, naphthalene, anthracene, phenanthrene, diphenylene oxide, thianthrene, phenothioxine, diphenylene sulfide, phenothiazine, diphenyl oxide, diphenyl sulfide, diphenylamine, cyclohexane, petroleum naphthenes, decahydro-naphthalene, cyclopentane, etc.; R3 in Formula I is an aliphatic group such as alkyl, alkenyl, alkoxy, alkoxyalkyl, carboalkoxyalkyl, etc.; x is at least 1, and (R3)x+T contains a total of at least 15 carbon atoms, R4 in Formula II is an aliphatic group containing at least about 9, preferably at least about 12 and often at least about 15 carbon atoms and M is a metal cation. Examples of type of the R4 radical are alkyl, alkenyl, alkoxyalkyl, carboalkoxyalkyl, etc. Specific examples of R4 are groups derived from petrolatum, saturated and unsaturated paraffin wax, and polyolefins, including polymerized C2, C3, C4, C5, C6, etc., olefins containing up to about 7000 carbon atoms in the polymer. The groups T, R3, and R4 in the above formulae can also contain other inorganic or organic substituents in addition to those enumerated above such as, for example, hydroxy, mercapto, halogen, nitro, amino, nitroso, sulfide, disulfide, etc. In the above Formulae I and II, each of x, y, z and f and g, i, and h is at least 1.
Specific examples of sulfonic acids useful in this invention are mahogany sulfonic acids; bright stock sulfonic acids; sulfonic acids derived from lubricating oil fractions having a Saybolt viscosity from about 100 seconds at 100xc2x0 F. to about 200 seconds at 210xc2x0 F.; petrolatum sulfonic acids; mono- and poly-wax substituted sulfonic and polysulfonic acids of, e.g., benzene, naphthalene, phenol, diphenyl ether, naphthalene disulfide, diphenylamine, thiophene, alpha-chloronaphthalene, etc.; other substituted sulfonic acids such as alkyl benzene sulfonic acids (where the alkyl group has at least 8 carbons), cetylphenol mono-sulfide sulfonic acids, dicetyl thianthrene disulfonic acids, dilauryl beta naphthyl sulfonic acid, dicapryl nitronaphthalene sulfonic acids, and alkaryl sulfonic acids such as dodecyl benzene xe2x80x9cbottomsxe2x80x9d sulfonic acids.
The bottoms acids are derived from benzene which has been alkylated with propylene tetramers or isobutene trimers to introduce 1,2,3, or more branched-chain C12 substituents on the benzene ring. Dodecyl benzene bottoms, principally mixtures of mono- and di-dodecyl benzenes, are available as by-products from the manufacture of household detergents. Similar products obtained from alkylation bottoms formed during manufacture of linear alkyl sulfonates (LAS) are also useful in making the sulfonates used in this invention.
The production of sulfonates from detergent manufacture-by-products by reaction with, e.g., SO3, is well known to those skilled in the art. See, for example, the articles xe2x80x9cSulfonation and Sulfationxe2x80x9d, Vol. 23, pp. 146 at seq. and xe2x80x9cSulfonic Acidsxe2x80x9d, Vol. 23, pp. 194 et seq, both in Kirk-Othmer xe2x80x9cEncyclopedia of Chemical Technologyxe2x80x9d, Fourth Edition, published by John Wiley and Sons, N.Y. (1997).
Also included are aliphatic sulfonic acids containing at least about 7 carbon atoms, often at least about 12 carbon atoms in the aliphatic group, such as paraffin wax sulfonic acids, unsaturated paraffin wax sulfonic acids, hydroxy-substituted paraffin wax sulfonic acids, hexapropylene sulfonic acids, tetra-amylene sulfonic acids, polyisobutene sulfonic acids wherein the polyisobutene contains from 20 to 7000 or more carbon atoms, chloro-substituted paraffin wax sulfonic acids, nitroparaffin wax sulfonic acids, etc.; cycloaliphatic sulfonic acids such as petroleum naphthene sulfonic acids, cetyl cyclopentyl sulfonic acids, lauryl cyclohexyl sulfonic acids, bis-(di-isobutyl) cyclohexyl sulfonic acids, etc.
With respect to the sulfonic acids or salts thereof described herein and in the appended claims, it is intended that the term xe2x80x9cpetroleum sulfonic acidsxe2x80x9d or xe2x80x9cpetroleum sulfonatesxe2x80x9d includes all sulfonic acids or the salts thereof derived from petroleum products. A particularly valuable group of petroleum sulfonic acids are the mahogany sulfonic acids (so called because of their reddish-brown color) obtained as a by-product from the manufacture of petroleum white oils by a sulfonic acid process.
Other descriptions of overbased sulfonate salts and techniques for making them can be found in the following U.S. Pat. Nos. 2,174,110; 2,174,506; 2,174,508; 2,193,824; 2,197,800; 2,202,781; 2,212,786; 2,213,360; 2,228,598; 2,223,676; 2,239,974; 2,263,312; 2,276,090; 2,276,297; 2,315,514; 2,319,121; 2,321,022; 2,333,568; 2,333,788; 2,335,259; 2,337,552; 2,346,568; 2,366,027; 2,374,193; 2,383,319; 3,312,618; 3,471,403; 3,488,284; 3,595,790; and 3,798,012. These are hereby incorporated by reference for their disclosures in this regard.
Carboxylic acids from which suitable alkali and calcium overbased detergents for use in this invention can be made include aliphatic mono- and polybasic carboxylic acids. The aliphatic carboxylic acids generally contain at least 9 carbon atoms, often at least 15 carbon atoms and preferably at least 18 carbon atoms. Usually, they have no more than 400 carbon atoms. Generally, if the aliphatic carbon chain is branched, the acids are more oil-soluble for any given carbon atoms content. The aliphatic carboxylic acids can be saturated or unsaturated. Specific examples include linolenic acid, linoleic acid, behenic acid, isostearic acid, stearic acid, palmitoleic acid, lauric acid, oleic acid, ricinoleic acid, commercially available mixtures of two or more carboxylic acids, such as tall oil acids, rosin acids, and the like.
Preferred aliphatic carboxylic acids are of the formula 
wherein R5 is an aliphatic hydrocarbon-based group of at least 7 carbon atoms, often at least 12 carbon atoms and preferably, at least 15 carbon atoms, and not more than about 400 carbon atoms, and reactive equivalents thereof.
In another embodiment, the carboxylic acid is a hydrocarbyl-substituted carboxyalkylene-linked phenol; dihydrocarbyl ester of alkylene dicarboxylic acids, the alkylene group being substituted with a hydroxy group and an additional carboxylic acid group; alkylene-linked polyaromatic molecules, the aromatic moieties whereof comprise at least one hydrocarbyl-substituted phenol and at least one carboxy phenol; and hydrocarbyl-substituted carboxyalkylene-linked phenols.
These carboxylic compounds are prepared by reacting a phenolic reagent with a carboxylic reagent of the general formula
R1CO(CR2R3)xCOOR6
wherein R1, R2 and R3 are independently H or a hydrocarbyl group, R6 is H or an alkyl group, and x is an integer ranging from 0 to about and reactive equivalents thereof. Compounds of this type are described in several U.S. Patents including numbers U.S. Pat. Nos. 5,281,346; 5,336,278 AND 5,356,546.
Unsaturated hydroxycarboxylic compounds prepared by reacting olefinic compounds with this carboxylic compound are also useful. Compounds of this type are described in several U.S. Patents including U.S. Pat. Nos. 5,696,060; 5,696,067; 5,777,142 and 6,020,500.
Aromatic carboxylic acids are useful for preparing metal salts useful in the compositions of this invention. These include aromatic carboxylic acids such as hydrocarbyl substituted benzoic, phthalic and salicylic acids.
Salicylic acids and other aromatic carboxylic-acids are well known or can be prepared according to procedures known in the art. Carboxylic acids of this type and processes for preparing their neutral and basic metal salts are well known and disclosed, for example, in U.S. Pat. Nos. 2,197,832; 2,197,835; 2,252,662; 2,252,664; 2,714,092; 3,410,798; and 3,595,791. These patents are incorporated by reference for disclosure of carboxylic acids, their basic salts and processes of making the same.
In the context of this invention, phenols are considered organic acids. Thus, overbased salts of phenols (generally known as phenates) are also useful in making (A) of this invention and are well known to those skilled in the art.
A commonly available class of phenates are those made from phenols of the general formula 
wherein R5 is as described hereinabove, R6 is a lower aliphatic of from 1 to 6 carbon atoms, a is an integer of from 1 to 3, b is 1 or 2 and c is 0 or 1.
One particular class of phenates for use in this invention are the overbased phenates made by sulfurizing a phenol as described hereinabove with a sulfurizing agent such as sulfur, a sulfur halide or sulfide or hydrosulfide salt. Techniques for making sulfurized phenates are described in U.S. Pat. Nos. 2,680,096; 3,036,971; and 3,775,321 which are expressly incorporated herein by reference for their disclosures in this regard.
Other phenates that are useful are those that are made from phenols that have been linked through alkylene (e.g., methylene) bridges. These are made by reacting single or multi-ring phenols with aldehydes or ketones, typically in the presence of an acid or basic catalyst. Such linked phenates, as well as sulfurized phenates, are described in detail in U.S. Pat. No. 3,350,038; particularly columns 6-8, thereof which is expressly incorporated herein by reference for its disclosure in this regard.
Salicylic acids may be considered to be carboxylic acids or phenols. Hydrocarbyl substituted salicylic acids are useful for preparing metal salts useful in the compositions of this invention.
Preferred overbased metal salts are the hydrocarbyl substituted sulfonic acid salts.
The alkali metal and calcium overbased salts are present in the compositions used in this invention in relative amounts on a per 100 TBN and diluent free basis ranging from about (99.5-20) to about (0.5-80), preferably from about (99.5-40) to about (0.5-60), more preferably from about (99-45) to about (1-55) and most preferably from about (98-50) to about (2-50).
The following specific illustrative examples describe how to make alkali metal overbased detergents (A-1) and calcium overbased detergents (A-2). In these examples and in subsequent sets of example, as well as in this specification and the appended claims, all percentages, parts and ratios are by weight and temperatures are in degrees Celsius (xc2x0 C.) unless expressly stated otherwise. Filtrations are conducted using a diatomaceous earth filter aid.